The present invention relates to a novel .alpha.-cyanoacrylate and a cyanoacrylate-based adhesive composition containing same.
.alpha.-Cyanoacrylates such as methyl .alpha.-cyanoacrylate and ethyl .alpha.-cyanoacrylate are polymerized and cured rapidly by the action of a small amount of water present on the surface of a material to be bonded and afford an adhesive force of an extremely high strength, so are widely used as room-temperature one-pack type instantaneous adhesives for the bonding of metals, plastics, rubber, wood and the like.
As .alpha.-cyanoacrylate there are known propyl .alpha.-cyanoacrylate, allyl .alpha.-cyanoacrylate, propargyl .alpha.-cyanoacrylate, 2,2,2-trifluoroethyl .alpha.-cyanoacrylate, 2,2,3,3-tetrafluoropropyl .alpha.-cyanoacrylate, 2-methoxyethyl .alpha.-cyanoacrylate, 2-ethoxyethyl .alpha.-cyanoacrylate and the like in addition to the above mentioned methyl and ethyl .alpha.-cyanoacrylates.
Generally, in the case where an .alpha.-cyanoacrylate is used as an adhesive, a portion thereof voltilizes and is polymerized by water contained in the air and adheres as white powder to the surrounding portion of a bonded part (whitening phenomenon), thus impairing the appearance of the bonded material. When used in the assembly of electric and electronic parts, the volatilized monomer contaminates a contact portion and causes defective contact, or cures in a moving part, thereby causing malfunction. Moreover, the thermal stability of a cured product is not sufficient and the bonding strength is reduced rapidly over 100.degree. C. It is known that .alpha.-cyanoacrylates having an unsaturated bond in the ester portion have improved thermal stability. In this case the cured or adhered portion is heat treated at an appropriate temperature (100.degree. C.-150.degree. C.) in order to improve the thermal stability. However, the adhesive properties at a high temperature are not improved.
It is the object of the present invention to overcome the above mentioned drawbacks of the prior art. More concretely, it is the object of the present invention to provide a novel compound having superior adhesive properties as an instantaneous adhesive and superior in whitening-preventing property and thermal stability including high temperature adhesive properties.